在 terraform 中，如何将传入的变量用于地图？

Question

使用 terraform v0.12.3

$ terraform version
Terraform v0.12.3
+ provider.aws v2.20.0

我的 variables.tf 文件中有这个映射变量

variable "subnet_id" {
  type = map
  description = "Subnet to use"
  default = {
    sandbox = {
      us-east-1a = "subnet-1234"
      us-east-1b = "subnet-2345"
      us-east-1c = "subnet-3456"
      us-east-1d = ""
      us-east-1e = ""
      us-east-1f = ""
    }
    staging = {
      us-east-1a = "subnet-4567"
      us-east-1b = "subnet-5678"
      us-east-1c = "subnet-6789"
      us-east-1d = ""
      us-east-1e = ""
      us-east-1f = ""
    }
    production = {
      us-east-1a = "subnet-7890"
      us-east-1b = "subnet-0987"
      us-east-1c = "subnet-9876"
      us-east-1d = "subnet-8765"
      us-east-1e = "subnet-7654"
      us-east-1f = ""
    }
  }
}

如何通过传递环境变量来获取我想要的子网 ID？ IOW，我想……

$ terraform plan -var 'environment=sandbox'

在我的 main.tf 代码中

module "jenkins_slave" {
  subnet_id = var.subnet_id[var.environment["us-east-1a"]]
  ....
}

我明白了

$ terraform plan -var environment="sandbox"
Error: Invalid index

  on main.tf line 17, in module "jenkins-slaves":
  17:   subnet_id         = var.subnet_id[var.environment["us-east-1a"]]
    |----------------
    | var.environment is "sandbox"

This value does not have any indices.

就我而言，我希望subnet_id 密钥最终等于subnet-1234

Answer 1

首先，为了能够传递一个变量，你需要在你的代码中定义它：

variable "environment" {}

此外，您需要使用var.subnet_id[var.environment]["us-east-1a"]，而不是var.subnet_id[var.environment["us-east-1a"]]。

否则，var.environment["us-east-1a"] 指的是environment 映射的us-east-1a 键。在您的情况下，environment 只是一个字符串而不是地图，因此 Terraform 会引发错误：This value does not have any indices.。

附：看来，你的variable "subnet_id" {...}也有错字，ssandbox应该是sandbox。